System and method of measuring real-time current

ABSTRACT

A system and method of measuring real-time current is disclosed. The method includes calibrating a voltage measurement device. Calibrating includes measuring a real-time voltage difference between a first measurement node located proximate a first connector on a motherboard and a second measurement node located proximate a second connector on a power supply unit (PSU), the first and the second connectors coupled to provide power to the motherboard. Calibrating further includes averaging the real-time voltage difference for a plurality of measurements; computing a resistance of the coupling based at least on a long-duration averaged current from the PSU and the averaged real-time voltage difference, the resistance varying over time; and reporting the resistance of the coupling to the voltage measurement device. The method also includes measuring a real-time current of the PSU at the voltage measurement device based at least on the resistance of the coupling and the real-time voltage difference.

TECHNICAL FIELD

The present disclosure relates generally to information handlingsystems, and more particularly to measuring real-time current of a powersupply associated with an information handling system.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

As processors, graphics cards, random access memory (RAM) and othercomponents in information handling systems have increased in clock speedand power consumption, the amount of current required for thesecomponents has increased. However, excessive current draw may damagecomponents of an information handling system. It may be desirable tomeasure the current being drawn from a power supply to power componentsof the information handling system. Some attempts to measure current mayuse sense components, but this may result in a substantial power loss.Some attempts may use attempts to measure at the power supply, but thismay be very costly to implement or very slow.

SUMMARY

In one embodiment, a method is described including calibrating a voltagemeasurement device. Calibrating the voltage measurement device includesmeasuring a real-time voltage difference between a first measurementnode located proximate a first connector on a motherboard and a secondmeasurement node located proximate a second connector on a power supplyunit (PSU), the first and the second connectors coupled to provide powerto the motherboard. Calibrating the voltage measurement device furtherincludes averaging the real-time voltage difference for a plurality ofmeasurements, computing a resistance of the coupling between the firstand the second connectors based at least on a long-duration averagedcurrent from the PSU and the averaged real-time voltage difference, theresistance varying over time, and reporting the resistance of thecoupling to the voltage measurement device. The method also includesmeasuring a real-time current of the PSU at the voltage measurementdevice based at least on the resistance of the coupling and thereal-time voltage difference.

In another embodiment, an information handling system is disclosed. Theinformation handling system includes a motherboard comprising a firstconnector for coupling to another connector and a first measurement nodepositioned proximate the first connector on the motherboard. Theinformation handling system also includes a power supply unit (PSU)comprising a second connector coupled to and supplying power to themotherboard via the first connector, the coupling of the first and thesecond connectors having a resistance that varies over time, and asecond measurement node positioned proximate the second connector on thePSU. The information handling system further includes a voltagemeasurement device configured to measure a real-time voltage differencebetween the first measurement node and the second measurement node andmeasure a real-time current of the PSU based at least on the real-timevoltage difference between the first and the second measurement nodesand the resistance of the coupling. The information handling system alsoincludes a calibrating device configured to calibrate the voltagemeasurement device. The calibrating device is further configured toreceive a long-duration averaged current from the PSU, average themeasured real-time voltage difference between the first and the secondmeasurement nodes at a plurality of time increments, compute theresistance of the coupling based at least on the averaged measuredreal-time voltage and the long-duration averaged current, and report theresistance of the coupling to the voltage measurement device.

In a further embodiment, an information handling system is disclosed.The information handling system includes a motherboard comprising afirst connector for coupling to another connector and a firstmeasurement node positioned proximate the first connector on themotherboard. The information handling system also includes a powersupply unit (PSU) comprising a second connector coupled to and supplyingpower to the motherboard via the first connector, the coupling of thefirst and the second connectors having a resistance that varies overtime, and a second measurement node positioned proximate the secondconnector on the PSU. The information handling system further includes avoltage measurement device configured to measure a real-time voltagedifference between the first measurement node and the second measurementnode. The information handling system also includes a trip pointdetector configured to receive and retain a trip point voltage, receivethe real-time voltage difference from the voltage measurement device,compare the trip point voltage to the real-time voltage difference, andgenerate a signal based on the real-time voltage difference exceedingthe trip point voltage. The information handling system further includesa calibrating device configured to generate the trip point voltage. Thecalibrating device is further configured to receive a long-durationaveraged current from the PSU, average the measured real-time voltagedifference between the first and the second measurement nodes for aplurality of measurements, compute the resistance of the coupling basedat least on the averaged measured real-time voltage and thelong-duration averaged current, and update the trip point voltage basedat least on the computed resistance of the coupling.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the disclosed embodiments andadvantages thereof may be acquired by referring to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numbers indicate like features, and wherein:

FIG. 1 illustrates a block diagram of an example information handlingsystem, in accordance with the present disclosure;

FIG. 2 illustrates a block diagram of an alternative example informationhandling system, in accordance with the present disclosure;

FIG. 3 illustrates an example of a set of operations to detect real-timecurrent, in accordance with the present disclosure;

FIG. 4 illustrates an alternative example of a set of operations todetect real-time current, in accordance with the present disclosure; and

FIG. 5 illustrates an example embodiment of analog circuitry, inaccordance with the present disclosure.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood byreference to FIGS. 1-5, wherein like numbers are used to indicate likeand corresponding parts.

For the purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, calculate, determine, classify, process, transmit, receive,retrieve, originate, switch, store, display, communicate, manifest,detect, record, reproduce, handle, or utilize any form of information,intelligence, or data for business, scientific, control, or otherpurposes. For example, an information handling system may be a personalcomputer (e.g., desktop or laptop), tablet computer, mobile device(e.g., personal digital assistant (PDA) or smart phone), server (e.g.,blade server or rack server), a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include random accessmemory (RAM), one or more processing resources such as a centralprocessing unit (CPU) or hardware or software control logic, ROM, and/orother types of nonvolatile memory. Additional components or theinformation handling system may include one or more disk drives, one ormore network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse,touchscreen and/or a video display. The information handling system mayalso include one or more buses operable to transmit communicationbetween the various hardware components.

For the purposes of this disclosure, computer-readable media may includeany instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory; aswell as communications media such as wires, optical fibers, microwaves,radio waves, and other electromagnetic and/or optical carriers; and/orany combination of the foregoing.

FIG. 1 illustrates a block diagram of an example information handlingsystem 100, in accordance with certain embodiments of the presentdisclosure. In certain embodiments, information handling system 100 maycomprise a computer chassis or enclosure (e.g., a server chassis holdingone or more server blades). In other embodiments, information handlingsystem 100 may comprise a storage enclosure. In yet other embodiments,information handling system 100 may be a personal computer (e.g., adesktop computer or a portable computer). As depicted in FIG. 1,information handling system 100 may include a processor 110, a memory120, a motherboard 130, a power supply unit (PSU) 140, a voltagemeasurement device 150, a calibrating device 160, a motherboardconnector 170 a, a power supply connector 170 b, a motherboardmeasurement node 180 a, and a power supply measurement node 180 b. Insome embodiments, voltage measurement device 150 may further include atrip point detector 155, or trip point detector 155 may be a stand-alonecomponent. Information handling system 100 may also include a controller190. Information handling system 100 may be configured to providereal-time measurement of current being delivered by PSU 140 tomotherboard 130 by using Ohm's Law and measuring a voltage differencebetween the two measurement nodes 180 a and 180 b and knowing theresistance of the coupling between PSU 140 and motherboard 130. However,the resistance of the coupling may vary over time so calibrating device160 may be configured to facilitate calibrating voltage measurementdevice 150 to provide accurate current readings

Processor 110 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data, andmay include, without limitation a microprocessor, microcontroller,digital signal processor (DSP), application specific integrated circuit(ASIC), or any other digital or analog circuitry configured to interpretand/or execute program instructions and/or process data. In someembodiments, processor 110 may interpret and/or execute programinstructions and/or process data stored in memory 120 and/or anothercomponent of information handling system 100. Although FIG. 1 depictsinformation handling system 100 as including one processor 110,information handling system 100 may include any suitable number ofprocessors 110.

Memory 120 may be communicatively coupled to processor 110 and mayinclude any system, device, or apparatus configured to retain programinstructions and/or data for a period of time (e.g., computer-readablemedia). Memory 120 may include random access memory (RAM), electricallyerasable programmable read-only memory (EEPROM), a PCMCIA card, flashmemory, magnetic storage, opto-magnetic storage, or any suitableselection and/or array of volatile or non-volatile memory that retainsdata after power to information handling system 100 is turned off.Although FIG. 1 depicts information handling system 100 as including onememory 120, information handling system 100 may include any suitablenumber and variety of memories 120.

Motherboard 130 may be any component or set of components configured tofacilitate communication among and between components of informationhandling system 100. For example, motherboard 130 may include a printedcircuit board with a variety of connectors thereon that variouscomponents of information handling system 100 may interface with. Insome embodiments, motherboard 130 may have designated interfaces for anyof processor 110, memory 120, PSU 140, voltage measurement device 150,calibrating device 160, controller 190, a graphics processing unit(GPU), a network interface card (NIC), or any combinations thereof. Insome embodiments, motherboard 130 may distribute power from PSU 140 toother components of information handling system 100. For example,motherboard 130 may distribute power to one or more processors 110 ofinformation handling system 100.

Motherboard connector 170 a may be a connector configured to interfacewith PSU 140. In some embodiments, connector 170 a may be a dedicatedinterface for exclusively connecting to one or more PSUs 140. Forexample, connector 170 a may be a male or a female end of a connectionpair. In other embodiments, connector 170 a may be a generic connectorof motherboard 130 that is capable of interfacing with any of a varietyof components of information handling system 100, including PSU 140. Insome embodiments, connector 170 a may have features for receiving powerfrom PSU 140 and other features for providing data communication withPSU 140. For example, connector 170 a may have a series of wires or pinsconfigured to receive data from or send data to PSU 140.

PSU 140 may be electrically coupled to various components of informationhandling system 100 and may include any device, system, or apparatusoperable to supply electrical energy to one or more components ofinformation handling system 100. Although FIG. 1 depicts informationhandling system 100 as including one PSU 140, information handlingsystem 100 may include any suitable number of PSUs 140. As shown in FIG.1, in some embodiments, PSU may directly supply electrical energy tomotherboard 130, which may then distribute electrical energy to variousother components of information handling system 100.

PSU 140 may be configured to provide a variety of default informationand messages to components of information handling system 100. Forexample, in some embodiments, PSU 140 may slowly measure, average, andreport the current flowing through PSU 140 over a long duration. Thismay occur on the order of seconds or tenths of seconds. For example, PSU140 may report the current flowing through PSU 140 once per second. Thismay be represented by the variable I_(long). Such slow reporting may betoo slow for dynamic power management, to prevent PSU 140 shut down, orto prevent or mitigate damage to components of information handlingsystem 100, including PSU 140.

Power supply connector 170 b may be a connector configured to interfacewith motherboard 130. In some embodiments, connector 170 b may be adedicated interface for exclusively connecting to motherboard 130. Forexample, connector 170 a may be a male or a female end of a connectionpair. In other embodiments, connector 170 b may be a generic connectorthat is capable of interfacing with any of a variety of components ininformation handling system 100. In some embodiments, connector 170 bmay have features for delivering power to motherboard 130 and otherfeatures for providing data communication with motherboard 130. Forexample, connector 170 b may have a series of wires or pins configuredto receive data from or send data to motherboard 130. In someembodiments, PSU 140 may report the long-duration averaged I_(long) tomotherboard 130 via connector 170 b, or it may be sent to calibratingdevice 160 via some other communication channel. In some embodiments,motherboard 130 may then communicate I_(long) to calibrating device 160.

Motherboard connector 170 a and power supply connector 170 b may becoupled to allow electrical power to flow from PSU 140 to motherboard130. The coupling of the two connectors 170 a and 170 b may have aresistance associated with electrical current passing from PSU 140 tomotherboard 130. This resistance may be represented by the variableR_(couple). R_(couple) may vary over time. For example, when informationhandling system 100 is first turned on, the ambient temperature withininformation handling system 100 may be relatively cool, such thatconnectors 170 a and 170 b may have a given resistance. As timeprogresses and components within information handling system 100generate heat, connectors 170 a and 170 b may increase in temperature,thus varying the resistance of the coupling of the two connectors. Forexample, for most metals, as temperature increases, resistance increasesbased on a temperature coefficient of resistance or resistivity for thegiven material.

Voltage measurement device 150 may include any system, device, orapparatus configured to rapidly measure a voltage change between twopoints. For example, voltage measurement device 150 may include analogcircuitry, digital circuitry, logic, or combination thereof configuredto measure a voltage change between two points. In some embodiments,voltage measurement device 150 may also be configured to measure acurrent based on a measured voltage. For example, using Ohm's Law(I=V/R), with a known resistance between two points, voltage measurementdevice 150 may be able to measure a current between two points based onan observed voltage difference between the two points. It will beappreciated that the term voltage difference may include anyrelationship between two measurements of voltage, including an increase,a decrease, or equivalent values. Voltage measurement device 150 may behoused, attached, or configured to be part of motherboard 130, PSU 140,or may be a free-standing component. Voltage measurement device 150 maybe configured to provide essentially instantaneous or real-time voltagedifference measurements. For example, voltage measurement device 150 mayprovide real-time voltage measurements on the order of microseconds, forexample, every 0.1, 1, 5, 10, 20, 50, or 100 microseconds.

In some embodiments, voltage measurement device 150 may be implementedas a voltmeter. When implemented as analog circuitry, voltagemeasurement device 150 may include op-amps, resistors, and/or capacitorsconfigured such that the voltage difference between two points may bemeasured. When implemented as digital circuitry, voltage measurementdevice 150 may include front amps and analog to digital convertersconfigured such that the voltage difference between two points may bemeasured. In some embodiments, either the analog or digital circuitrymay be configured to amplify, filter, or both, the signal carrying ameasurement.

Measurement nodes 180 a and 180 b may be any point from which voltagemeasurement device 150 may take voltage measurements. Measurement nodesmay be a wire, a printed circuit, or any other feature or component ableto carry a voltage signal. Measurement node 180 a may be positionedproximate motherboard connector 170 a on motherboard 130 such thatvoltage measurement device 150 may have one voltage measurement pointjust after electrical power is passed from PSU 140 to motherboard 130.Measurement node 180 b may be positioned proximate power supplyconnector 170 b such that voltage measurement device 150 may have avoltage measurement point just before electrical power is passed fromPSU 140 to motherboard 130. In some embodiments, measurement nodes 180 aand 180 b may be associated with unused communication pins between PSU140 and motherboard 130. In some embodiments, two current sense pins maybe defined on power supply connector 170 b such that sense signals fromnodes 180 a and 180 b may be communicated to voltage measurement device150 with limited or no power flowing impact regardless of where voltagemeasurement device 150 or calibrating device 160 may be located. In someembodiments this may include pins associated with connector 170 a, 170b, or both. For example, if the combination of 170 a and 170 b is amale/female connection, there may be corresponding pin functionality onboth 170 a and 170 b when they are coupled together.

Voltage measurement device 150 may be configured to take real-timemeasurements of the voltage difference between two points. For example,voltage measurement device 150 may take real-time measurements of thevoltage difference between measurement nodes 180 a and 180 b. This maybe represented by the variable V_(real). This may correspond to thereal-time voltage difference observed by passing the current from PSU140 to motherboard 130. While voltage measurement device 150 may impartsome resistance by measuring the voltage difference and thus draw aminimal current to take measurements, it will be appreciated that thisresistance may be negligible when compared to the resistance from thecoupling of motherboard connector 170 a and power supply connector 170b. In some embodiments, the resistance from voltage measurement device150 may be ignored when measuring the voltage difference betweenmeasurement nodes 180 a and 180 b. In other embodiments, the resistanceof voltage measurement device 150 may be known and may be included inany analysis regarding voltage differences measured by voltagemeasurement device 150.

The minimal current from measurement nodes 180 a and 180 b may be passedalong a data communication channel between PSU 140 and motherboard 130.For example, the data communication link between PSU 140 and motherboard130 may carry the minimal current from node 180 a to voltage measurementdevice 150 when voltage measurement device 150 is located on PSU 140.Alternatively, the data communication link may carry the minimal currentfrom measurement node 180 b when voltage measurement device 150 islocated on motherboard 130. In some embodiments, this may be a dedicatedpin of the data communication link between PSU 140 and motherboard 130.

Calibrating device 160 may include any system, device, or apparatusconfigured to calibrate voltage measurement device 150. Calibratingdevice 160 may include analog circuitry, digital circuitry, logic,software, hardware, or any combination thereof. Calibrating device 160may be in communication with PSU 140 either directly or indirectly suchthat calibrating device 160 may receive the long-duration averagedcurrent of PSU 140, I_(long). Calibrating device 160 may also be incommunication with voltage measurement device 150 such that calibratingdevice 160 may receive the real-time measurements of the voltagedifference between measurement nodes 180 a and 180 b taken by voltagemeasurement device 150, V_(real). Calibrating device 160 may average thereal-time voltage difference V_(real) for a plurality of time incrementsto determine an average voltage difference for a given time period. Thismay be represented by the variable V_(avg). For example, calibratingdevice 160 may take a plurality of measurements from within the timespan from which PSU 140 has reported the long-duration averaged currentI_(long). Alternatively, in some embodiments, calibrating device 160 maykeep a rolling average of a certain number of real-time measurements ofV_(real) from voltage measurement device 150 to acquire V_(avg) tocorrespond with the long-duration averaged current I_(long) periodicallyreported by PSU 140.

Calibrating device 160 may be configured to compute R_(couple) based onthe long-duration averaged current I_(long) reported by PSU 140 and theaveraged real-time measurements of the voltage measured by voltagemeasurement device 150 V_(avg). For example, using Ohm's Law, with aknown current I_(long) and an averaged voltage V_(avg) known tocorrespond to that current, R_(couple) may be computed. For example,

R _(couple) =V _(avg) /I _(long)

Calibrating device 160 may then report this computed value of R_(couple)to voltage measurement device 150. This may in turn enable voltagemeasurement device 150 to calculate in real-time the current flow comingfrom PSU 140 to motherboard 130 based on the known resistanceR_(couple). This may be represented by the variable I_(real) and may bemeasured as described above.

As described above, R_(couple) may be variable over time. Thus, in someembodiments, calibrating device 160 may continuously or periodicallyrecalibrate voltage measurement device 150 by re-computing R_(couple).For example, in some embodiments, calibrating device 160 may beconfigured to compare a rolling value of V_(avg) to each reported valueof I_(long) to continuously compute R_(couple). In alternativeembodiments, calibrating device 160 may be configured to periodicallysample the latest received or next arriving I_(long) and compare it to acorresponding value of V_(avg). For example, calibrating device 160 mayperiodically compute R_(couple) every 0.5, 1, 1.5, 2, or 5 seconds, orany other frequency sufficient to guard against excessive changes toR_(couple). Calibrating device 160 may be configured to only reportR_(couple) to voltage measurement device 150 if R_(couple) has changedsince the previous value of R_(couple) reported to voltage measurementdevice 150.

In some embodiments, voltage measurement device 150 and calibratingdevice 160 may be part of PSU 140 rather than associated withmotherboard 130. In such an embodiment, measurement nodes 180 a and 180b may connect to voltage measurement device 150 on PSU 140 rather thanto motherboard 130. Additionally, any computing or processing may beperformed by a processor, logic or other feature of PSU 140, for examplea PSU controller.

In some embodiments, information handling system 100 may additionallyinclude a trip point detector 155. Trip point detector 155 may includeany system, device, or apparatus configured to detect a trip pointassociated with measurements taken by voltage measurement device 150.Trip point detector 155 may include analog circuitry, digital circuitry,logic, software, hardware, or any combination thereof. For example, trippoint detector 155 may be any comparator circuit like an op amp or adedicated comparator chip. The trip point associated with trip pointdetector may be based on a voltage or a current. For example, trip pointdetector 155 may be configured to compare a trip point voltage toV_(real). In other embodiments, trip point detector 155 may beconfigured to compare a trip point current to I_(real). Trip pointdetector 155 may determine whether the measured value, for exampleV_(real) or I_(real) has exceeded the trip point. If the measured valuehas exceeded the trip point, trip point detector 155 may generate asignal indicating that this has occurred. This may be used by any of avariety of components within information handling system 100. Forexample, this may be used to initiate throttling of processor 110,generating a PROCHOT# signal, turning on another power supply, turningoff or throttling other components, turning on or speeding up othercomponents (like fans), notifying a user of information handling system100, or any combinations thereof.

The trip point may be provided by any of a variety of components ofinformation handling system 100. For example, trip point detector 155may receive the trip point from processor 110, controller 190, voltagemeasurement device 150, calibrating device 160, or power supply 140.

In some embodiments, voltage measurement device 150 may include trippoint detector 155. In other embodiments, trip point detector 155 may bea free standing component, or may be part of calibrating device 160. Insome embodiments, the communication between voltage measurement device150, trip point detector 155, and calibrating device 160 may be a closedloop system such that voltage measurement device 150 provides data totrip point detector 155 and calibrating device 160, and calibratingdevice 160 provides data to trip point detector 155 and/or voltagemeasurement device 150.

Controller 190 may include any system, device, or apparatus configuredto interpret and/or execute program instructions and/or process data,and may include, without limitation a microprocessor, microcontroller,digital signal processor (DSP), application specific integrated circuit(ASIC), or any other digital or analog circuitry configured to interpretand/or execute program instructions and/or process data. In someembodiments, controller 190 may interpret and/or execute programinstructions and/or process data stored in memory 120 and/or anothercomponent of information handling system 100. In certain embodiments,controller 190 may include or may be an integral part of a baseboardmanagement controller (BMC), Dell Remote Access Controller (DRAC) or anIntegrated Dell Remote Access Controller (iDRAC).

In some embodiments, controller 190 may be in communication with,cooperation with, control of, or an integral part of some or all of thecomponents described herein. For example, in some embodiments, any ofvoltage measurement device 150, trip point detector 155, calibratingdevice 160, PSU 140, processor 110, memory 120 and combinations thereofmay be configured to be controlled by or receive instructions fromcontroller 190. In some embodiments, the functionality or features ofone or all of voltage measurement device 150, trip point detector 155,and calibrating device 160 may be performed by controller 190. Forexample, in some embodiments, voltage measurement device 150, trip pointdetector 155, and calibrating device 160 may be an integral part ofcontroller 190. In such an embodiment, the signal generated by trippoint detector 155 may enable controller 190 to initiate any or all ofthe actions which may occur when a measured value exceeds the trippoint.

In an alternative embodiment shown in FIG. 2, voltage measurement device150 may only measure the real-time voltage difference V_(real) betweenmeasurement nodes 180 a and 180 b. In such an embodiment, trip pointdetector 155 may utilize a trip point voltage rather than a trip pointcurrent to determine whether a measured value has exceeded a given trippoint or threshold. In such an embodiment, the calibration is alsoslightly modified. As described above, calibrating device 160 maycompute R_(couple) using I_(long) and an averaged voltage V_(avg).However, rather than reporting R_(couple) to voltage measurement device150, calibrating device 160 may use R_(couple) to determine any changesto the trip point voltage. Thus, rather than voltage measurement device150 solving for current using R_(couple), calibrating device 160 woulduse changes in R_(couple) to provide trip point detector 155 changes tothe trip point voltage. For example, based on Ohm's Law, if R_(couple)doubled in value, the value of the trip point voltage may be cut inhalf. In other words, the value of R_(couple) may have an inverserelationship with the trip point value.

In such an embodiment, calibrating device 160 may be configured to usethe received V_(real) signal from voltage measurement device 150 todetermine I_(real). In some embodiments, voltage measurement device 150may take an analog measurement, and simply pass the analog signal of themeasured value V_(real) to trip point detector 155. The analog signalfrom voltage measurement device 150 may also pass to an analog todigital converter to then pass a digital signal to calibrating device160. Calibrating device 160 may then use the digital signal of V_(real)to compute R_(couple) and to measure I_(real).

In some embodiments this may provide certain advantages over otherattempts to measure current. For example, embodiments of the presentdisclosure may allow for faster measurement times (for example,twenty-five times faster) when compared to a general PSU inductor outputreported to the system, which may only provide responses every 10-100milliseconds. As another example, embodiments of the present disclosuremay facilitate real-time current demands at the motherboard, which mayprovide a more accurate reading when compared to sense components thatmay not sense all components of a system. As a further example,embodiments of the present disclosure may provide an essentiallylossless approach, in other words, almost no power may be used inmeasuring the current. As a final example, the cost both in power andmoney of using shunt resistors at a motherboard may be saved. Theseexamples are in no way limiting, and merely serve as illustrations ofsome advantages of some embodiments of the present disclosure over otherattempts to measure current.

FIG. 3 illustrates an example of a set of operations to detect real-timecurrent, in accordance with the present disclosure. As shown in FIG. 3,operation 305 may include measuring the real-time voltage differencebetween measurement nodes 180 a and 180 b, V_(real). For example,voltage measurement device 150 may measure V_(real). Operation 310 mayinclude averaging the measured real-time voltage V_(real) to acquireV_(avg). This may include voltage measurement device 150 sendingV_(real) to calibrating device 160, which may average a plurality ofmeasurements V_(real) to acquire V_(avg). Operation 315 may includecomputing R_(couple) based at least on I_(long) and voltage V_(avg). Forexample, calibrating device 160 may receive I_(long) from PSU 140 andthen use I_(long) and voltage V_(avg) to compute R_(couple). Operation320 may include reporting the computed value of R_(couple) bycalibrating device 160 to voltage measurement device 150. In someembodiments, operations 305, 310, 315, and 320 may be continuously orperiodically repeated so as to update the value of R_(couple), asR_(couple) may vary over time. Calibrating a voltage measurement devicemay be associated with operations 305, 310, 315, and 320.

Operation 325 may include using the computed value of R_(couple) andreal-time measure voltage to calculate real-time current, I_(real).

Operation 330 may include receiving and retaining a trip point. Forexample, this may include processor 110 or controller 190 sending trippoint detector 155 a trip point current value. Operation 335 may includereceiving the real-time measured current I_(real). For example, this mayinclude trip point detector 155 receiving the real-time measured currentI_(real) from voltage measurement device 150. Operation 340 may includecomparing the measured real-time current I_(real) to the trip point. Atdecision 345, it may be determined whether I_(real) exceeds the trippoint. If not, the process may return to operation 335. If it isdetermined that the measured real-time current I_(real) exceeds the trippoint, operation 350 may include trip point detector 155 generating asignal indicating this has occurred.

FIG. 4 illustrates an alternative example of a set of operations todetect real-time current, in accordance with the present disclosure. Asshown in FIG. 4, operation 405 may include measuring the real-timevoltage difference between measurement nodes 180 a and 180 b, V_(real).For example, voltage measurement device 150 may measure V_(real).Operation 410 may include averaging the measured real-time voltageV_(real) to acquire V_(avg). This may include voltage measurement device150 sending V_(real) to calibrating device 160, which may average aplurality of measurements V_(real) to acquire V_(avg). Operation 415 mayinclude computing R_(couple) based at least on I_(long) and voltageV_(avg). For example, calibrating device 160 may receive I_(long) fromPSU 140 and then use I_(long) and voltage V_(avg) to compute R_(couple).Operation 420 may using the computed value of R_(couple) to update thetrip point voltage include by calibrating device 160. In someembodiments, operations 405, 410, 415, and 420 may be continuously orperiodically repeated so as to update the value of R_(couple), asR_(couple) may vary over time. Determining R_(couple) may includeoperations 405, 410, 415, and 420.

Operation 425 may include initializing the trip point voltage. This maybe used by calibrating device 160 as a baseline from which to updatebased on variations in R_(couple). This may also be used by trip pointdetector 155 as an initial trip point for comparison. This may begenerated by any of processor 110, controller 190, calibrating device160, or PSU 140. For example, processor 110 may read the initial trippoint value from memory 120 and send that value to calibrating device160 and trip point detector 155.

Operation 430 may include receiving and storing a trip point. Forexample, this may include processor 110 or controller 190 sending trippoint detector 155 an initial trip point voltage value. Alternatively,this may include calibrating device 160 sending trip point detector 155an updated trip point based on variations in R_(couple). Operation 435may include receiving the real-time measured voltage V_(real). Forexample, this may include trip point detector 155 receiving thereal-time measured voltage V_(real) from voltage measurement device 150.Operation 440 may include comparing the measured real-time voltageV_(real) to the trip point. At decision 445, it may be determinedwhether V_(real) exceeds the trip point. If not, the process may proceedback to operation 435. If it is determined that the measured real-timevoltage V_(real) exceeds the trip point, at operation 450 trip pointdetector 155 may generate a signal indicating this has occurred. Any ofthe resulting consequences of the signal may be expected as describedabove. Detecting a trip point may include operations 430, 435, 440, 445,and 450.

FIG. 5 illustrates an example embodiment of analog circuitry 500 inaccordance with some embodiments of the present disclosure. As will beappreciated, the circuitry shown in FIG. 5 is merely an example and isin no way limiting. As shown in FIG. 5, analog circuitry 500 may includemeasurement nodes 180 a and 180 b. Analog circuitry 500 may furtherinclude region 510 configured to measure the voltage, amplify thesignal, and compensate for temperature variations. Analog circuitry 500may further include region 520 configured to average and filter thesignal. The outgoing signal may be passed along line 530 to be used by aPSU, a motherboard, or some other system component.

Although the present disclosure has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made hereto without departing from the spirit and the scope of thedisclosure as defined by the appended claims.

What is claimed is:
 1. A method comprising: measuring a real-timevoltage difference between a first measurement node located proximate afirst connector on a motherboard and a second measurement node locatedproximate a second connector on a power supply unit (PSU), the first andthe second connectors coupled to provide power to the motherboard;averaging the real-time voltage difference for a plurality ofmeasurements; computing a resistance of the coupling between the firstand the second connectors based at least on a long-duration averagedcurrent from the PSU and the averaged real-time voltage difference, theresistance varying over time; and reporting the resistance of thecoupling to the voltage measurement device; and measuring a real-timecurrent of the PSU at the voltage measurement device based at least onthe resistance of the coupling and the real-time voltage difference. 2.The method of claim 1, further comprising detecting a trip pointcomprising: receiving and retaining a trip point current at a trip pointdetector; receiving the real-time current at the trip point detector;and comparing the trip point current and the real-time current.
 3. Themethod of claim 2, wherein the measuring, the calibrating, and the trippoint detecting are controlled by a controller separate from a mainprocessor of an information handling system.
 4. The method of claim 3,further including: alerting the controller if the real-time voltagedifference meets or exceeds the trip point voltage; and in response, thecontroller performing at least one of: asserting a PROCHOT signal;throttling the main processor; activating an alternate power supply; andnotifying a user of the information handling system.
 5. The method ofclaim 1, wherein the second measurement node is communicatively coupledto the voltage measurement device through a data connection between thePSU and the motherboard.
 6. The method of claim 1, wherein thelong-duration averaged current is sent to the calibrating device throughthe data connection between the PSU and the motherboard.
 7. The methodof claim 1, wherein the voltage measurement device is configured tomeasure the voltage difference at a frequency of between 0.1 and 100microseconds.
 8. The method of claim 1, wherein the voltage measurementdevice and the calibrating device are housed on the motherboard.
 9. Themethod of claim 1, wherein the voltage measurement device and thecalibrating device are housed on the PSU.
 10. An information handlingsystem, comprising: a motherboard comprising: a first connector forcoupling to another connector; and a first measurement node positionedproximate the first connector on the motherboard; a power supply unit(PSU) comprising: a second connector coupled to and supplying power tothe motherboard via the first connector, the coupling of the first andthe second connectors having a resistance that varies over time; and asecond measurement node positioned proximate the second connector on thePSU; a voltage measurement device configured to measure a real-timevoltage difference between the first measurement node and the secondmeasurement node and measure a real-time current of the PSU based atleast on the real-time voltage difference between the first and thesecond measurement nodes and the resistance of the coupling; and acalibrating device configured to calibrate the voltage measurementdevice, the calibrating device configured to: receive a long-durationaveraged current from the PSU; average the measured real-time voltagedifference between the first and the second measurement nodes at aplurality of time increments; compute the resistance of the couplingbased at least on the averaged measured real-time voltage and thelong-duration averaged current; and report the resistance of thecoupling to the voltage measurement device.
 11. The information handlingsystem of claim 10, the voltage measurement device further comprising atrip point detector, configured to: receive and retain a trip pointcurrent; receive the real-time current; and compare the trip pointcurrent and the real-time current.
 12. The information handling systemof claim 11, wherein the voltage measurement device and the calibratingdevice are controlled by a controller separate from a main processor ofthe information handling system.
 13. The information handling system ofclaim 12, wherein the trip point detector is further configured to alertthe controller if the real-time voltage difference meets or exceeds thetrip-point voltage, and in response, the controller is configured to doat least one of: assert a PROCHOT signal; throttle the main processor;activate an alternate power supply; and notify a user of the informationhandling system.
 14. The information handling system of claim 10,wherein the second measurement node is communicatively coupled to thevoltage measurement device through a data connection between the PSU andthe motherboard.
 15. The information handling system of claim 14,wherein the long-duration averaged current is sent to the calibratingdevice through the data connection between the PSU and the motherboard.16. The information handling system of claim 10, wherein the voltagemeasurement device is configured to measure the voltage difference at afrequency of between 0.1 and 100 microseconds.
 17. The informationhandling system of claim 10, wherein the voltage measurement device andthe calibrating device are housed on the motherboard.
 18. Theinformation handling system of claim 10, wherein the voltage measurementdevice and the calibrating device are housed on the PSU.
 19. Aninformation handling system, comprising: a motherboard comprising: afirst connector for coupling to another connector; and a firstmeasurement node positioned proximate the first connector on themotherboard; a power supply unit (PSU) comprising: a second connectorcoupled to and supplying power to the motherboard via the firstconnector, the coupling of the first and the second connectors having aresistance that varies over time; and a second measurement nodepositioned proximate the second connector on the PSU; a voltagemeasurement device configured to measure a real-time voltage differencebetween the first measurement node and the second measurement node; atrip point detector configured to: receive and retain a trip pointvoltage; receive the real-time voltage difference from the voltagemeasurement device; compare the trip point voltage to the real-timevoltage difference; and generate a signal based on the real-time voltagedifference exceeding the trip point voltage; and a calibrating deviceconfigured to generate the trip point voltage, the calibrating deviceconfigured to: receive a long-duration averaged current from the PSU;average the measured real-time voltage difference between the first andthe second measurement nodes for a plurality of measurements; computethe resistance of the coupling based at least on the averaged measuredreal-time voltage and the long-duration averaged current; and update thetrip point voltage based at least on the computed resistance of thecoupling.
 20. The information handling system of claim 19, wherein thevoltage measurement device sends the real-time voltage difference to thetrip point detector as an analog signal and sends the real-time voltageto the calibrating device via an analog to digital converter.